This invention relates to a plant monitoring system for displaying a process variable of a plant as a pictorial image on a display unit to thereby supervise or monitor the process variable.
For example, in a power generation plant, monitoring controls using a CRT display unit are widely adopted with the view of reducing the load on an operator and/or for improvement in the monitoring efficiency. For the content to be monitored, importance is attached to the monitoring of an operating process where the plant is in an unstable state, e.g., from startup of the power generation plant to ordinary operation thereof and/or from ordinary operation to shutdown of generation. Accordingly, there are provided many monitor screens for the unit of events or unit of systems adapted to the operating process. Such a monitoring system is exclusively directed to support of an operator with a view to stably operating the plant. In the event that any abnormal condition occurs, the investigation of the cause is ordinarily conducted by analyzing data such as plant data, afterwards. It is the present state of the art that detailed supervision up to such a level to investigate the cause on-line simultaneously with supervisory control of the operation cannot be carried out. Particularly, in a thermal power plant, as the profile of the power demand changes, plants in which daily startup and shutdown (DSS) use must be conducted for adjustment of the difference between power consumptions in the daytime and at night are increasing. In such plants, the states where plants become most unstable, such as startup and shutdown must be frequently repeated. Thus, more careful supervision than ever before becomes necessary. Such more careful supervision implies the feasibility of supervision having adaptability, or supervision capable of supporting abnormal cause diagnosis in an abnormal condition. To realize this, it is required to analyze one object to be supervised or monitored from every point of view, to conduct supervision while comparing individual objects to be supervised. Thus, the contents set for the monitor screen would increase and reach detailed levels.
The improvement in the ability of computers makes it possible to immediately analyze a great deal of data and to cope with an increase in the volume of data handled. However, unless an operator can effectively use such information, it will be dead or ineffective information. According as more careful supervision is required to a great extent, analysis of data becomes indispensable. In some cases, professional knowledge at the analytical level also becomes necessary. It is predicted that such supervision using analytical data will be increasingly needed in future. For effectively using such data on-line by an operator in the same manner as in conventional supervision, how such data is to be presented is a problem. Namely, data which is abundunt and of detailed levels cannot be effective information until an operator comprehends it and handles it in conformity with the operation of the plant.